Mid-Infrared Frequency Comb Generation and Spectroscopy with Few-Cycle Pulses and chi((2)) Nonlinear Optics

Author(s)

Lind, Alexander J. ^{[1, 2]} ; Kowligy, Abijith ^{[1, 2]} ; Timmers, Henry ^[2] ; Cruz, Flavio C. ^{[3, 2]} ; Nader, Nima ^[4] ; Silfies, Myles C. ^[5] ; Allison, Thomas K. ^[5] ; Diddams, Scott A. ^{[1, 2]}

Affiliation

^[1] Univ Colorado, Dept Phys, 2000 Colorado Ave, Boulder, CO 80309 - USA

^[2] NIST, Time & Frequency Div, 325 Broadway, Boulder, CO 80305 - USA

^[3] Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil

^[4] NIST, Appl Phys Div, 325 Broadway, Boulder, CO 80305 - USA

^[5] SUNY Stony Brook, Dept Chem & Phys, Stony Brook, NY 11794 - USA

• Document type: Journal article
• Source: Physical Review Letters; v. 124, n. 13 APR 1 2020.
• Web of Science Citations: 0

Abstract

The mid-infrared atmospheric window of 3-5.5 mu m holds valuable information regarding molecular composition and function for fundamental and applied spectroscopy. Using a robust, mode-locked fiberlaser source of < U fs pulses in the near infrared, we explore quadratic (chi((2))) nonlinear optical processes leading to frequency comb generation across this entire mid-infrared atmospheric window. With experiments and modeling, we demonstrate intrapulse difference frequency generation that yields few-cycle mid-infrared pulses in a single pass through periodically poled lithium niobate. Harmonic and cascaded chi((2)) nonlinearities further provide direct access to the carrier-envelope offset frequency of the near infrared driving pulse train. The high frequency stability of the mid-infrared frequency comb is exploited for spectroscopy of acetone and carbonyl sulfide with simultaneous bandwidths exceeding 11 THz and with spectral resolution as high as 0.003 cm(-1). The combination of low noise and broad spectral coverage enables detection of trace gases with concentrations in the part-per-billion range. (AU)

• FAPESP's process: 18/26673-5 - Spectroscopy and Sensing with Optical Frequency Combs: from DC to Visible
• Grantee: Flavio Caldas da Cruz
• Support Opportunities: Scholarships abroad - Research